Ultrasonic therapy is a well known and applied method in the area of physiotherapy.
During ultrasonic therapy ultrasonic energy is transmitted by means of a treatment head to the part of the body to be treated and its biological effect depends on the quantity of the ultrasonic energy transmitted to the patient's body. The ultrasonic energy exerts its health-giving effect in the body in two ways: directly influences the irradiated organ, on one hand in the form of mechanical and heating effects, on the other hand indirectly, i.e. transmitted by the sympathetic system. The ultrasonic therapy can be applied especially advantageously in the cases of rheumatological diseases, spinal complaints and in certain types of inflammations.
The efficiency of ultrasonic therapy depends to a great extent on the dose received by the patient. In order to ensure that the ultrasonic vibrations generated by the treatment head can penetrate into the patient's body, an appropriate coupling medium should be provided between the patient's body and the treatment head containing a piezo-electric converter. In the case, when the coupling between the patient's body and the treatment head is inappropriate, the efficiency of the treatment will decrease and the treatment itself becomes less reproducible. An inappropriate coupling can result from a coupling medium of low ultrasonic conductivity, from a low quantity of the coupling medium, from air bubbles in the coupling medium and the uneveness of the surface of the human body.
In the course of the treatment a continuously optimal coupling can not be guaranteed between the patient's body and the treatment head. This means that the intensity of ultrasonic energy I.sub.k measured on the body of the patient (ultrasonic energy pro surface unit, W/cm.sup.2) will not always be equal to the intensity of the ultrasonic energy measured on the treatment head. As a consequence, the patient will not get the predetermined dose. Hence the coupling factor can vary within broad limits and, in the known apparatus, there is no treatment time correction, the patient gets only a part of the necessary dose. Such known apparatus are made by the firms, as follows:
Mettler Electronis (USA): "Sonicator II" PA1 "Burdick UT 4300" PA1 Siemens Ag. (Germany): "Sonodinator" PA1 ERBE (Germany): "Erbosonat" PA1 OMSZOV (Hungary): "Ultron T"
(The last firm is identical with the assignee of applicant.)